There is great interest in finding methods that can be used to diagnosis, evaluate and/or monitor objectively the disease state referred to as chronic fatigue syndrome (CFS). As one example, an objective, saliva-based measurement tool would be useful in determining whether an individual is experiencing a level of fatigue sufficient to meet a diagnosis of chronic fatigue syndrome. Other applications include monitoring changes in fatigue level, e.g., in a subject diagnosed with CFS.
The present invention provides methods and compositions for diagnosing CFS, identifying subjects having an increased risk or likelihood of having or developing CFS and/or monitoring or evaluating fatigue in a subject by detecting and/or measuring biomarkers in one or more samples from the subject.